Figure 2.
Differences in glycemic response across baseline physical fitness
Boxplots represent the median and IQR of the data, cross symbols represent outlier values and each whisker extends to the most extreme data point that is not an outlier. ∗ represents significant differences p < 0.05 between boxplot groups as determined by an independent t-test. ∗∗ represents significant differences p < 0.05 between boxplot groups as determined by Wilcoxon rank-sum test. ○ represents significant differences p < 0.05 between sensor glucose as determined by a Wilcoxon rank-sum test.
(A) The slope of glucose during aerobic exercise is significantly steeper in participants with higher aerobic fitness (n = 88 observations collected from 11 participants) than participants with lower aerobic fitness (n = 70 observations collected from nine participants) (average trend −2.2 mg/dL/min vs −1.8 mg/dL/min, p = 0.03).
(B) The minimum glucose measured during aerobic exercise is significantly lower in participants with higher aerobic fitness (n = 88 observations collected from 11 participants) than in participants with lower aerobic fitness (n = 70 observations collected from nine participants) (average minimum glucose 75.9 mg/dL vs 103.1 mg/dL, p = 4.7 × 10−9).
(C) The minimum glucose measured by CGM in the 4-h following the start of aerobic exercise is significantly lower in participants with higher aerobic fitness (n = 88 observations collected from 11 participants) than in participants with lower aerobic fitness (n = 70 observations collected from nine participants) and (average minimum glucose 70.4 mg/dL vs 85.4 mg/dL, p = 3.3 × 10−5).
(D) IQR of sensor glucose obtained from participants during in-clinic study days 1 and 4. Participants with higher aerobic fitness exhibit significantly lower glucose during activities of daily living and aerobic exercise, and in the nighttime following exercise (p < 0.05). The lower aerobic fitness group is represented by gray area (n = 72 sensor traces collected from nine participants). The higher aerobic fitness group is represented by magenta area (n = 88 sensor traces collected from 11 participants). During the in-clinic exercise study visits, activities of daily living were performed starting at 10 a.m., and exercise at 70% VO2max was performed at 2 p.m. The number of sensor traces from 9 p.m.–12 a.m. is lower for both groups (lower fitness, n = 36, higher fitness, n = 44), representing data only from study day 1, whereas participants exited the clinical study on day 4 and overnight sensor data is therefore not available.
(E) IQR of sensor glucose across the entire 4-day study. The lower aerobic fitness group is represented by gray area (n = 36 sensor traces collected from nine participants). The higher aerobic fitness group is represented by magenta area (n = 44 sensor traces collected from 11 participants).